I own a carborated 85 trans am 305 5.0 and it was running fine until yesterday abd for whatever reason it wont even crank. I changed out the starter and jumped the battery(just incase) and all u hear is the sound of the starter hitting. The connector plugs to it look fine (no corrosion) Although I didnt shim the starter. Could thay possibly be the reason why it wont start? And if so how many shims would I need? And if not what ealse could cause this issue?